In the runup to this week’s successful test launch of SpaceX’s Falcon Heavy rocket, public attention was focused on CEO Elon Musk’s plan to launch a Tesla Roadster as a test payload. But it turns out that wasn’t all that was onboard.

In addition to a Tesla spacesuit and a stereo playing David Bowie’s “Space Oddity” on repeat, the Roadster, as reported by Mashable, was loaded up with a digital copy of the legendary Foundation science-fiction epic, encoded on an advanced crystal that could float through space for millions of years.

The Foundation trilogy, written by Isaac Asimov in the early 1950s, tells the convoluted but often mesmerizing tale of a human space empire attempting to preserve itself by building a huge library containing all human knowledge. The books launched Asimov’s career as one of the pre-eminent science fiction authors of all time, which he cemented with other works including I, Robot — recently loosely adapted into a Will Smith film — in which he laid out the now-famed Three Laws of Robotics.

Foundation’s inclusion in the mission echoes Musk’s longstanding enthusiasm for sci-fi. For instance, the autonomous barges that SpaceX uses to recover boosters, Just Read the Instructions and Of Course I Still Love You, take their names from similar space-empire novels by British author Iain M. Banks.

The story behind sending the Foundation books into space is nearly as interesting as the novels themselves. The Arch Mission Foundation, which according to TechCrunch was directly inspired by Asimov’s fictional comprehensive encyclopedia, wants to build a real-life database of all human knowledge. The library is set to be encoded in a variety of formats and sent off into the galaxy as a kind of ‘off-site backup.’

The discs sent up with Musk’s roadster are inscribed in a novel form of optical storage called a data crystal, which can hold an amazing 360 terabytes of data on a tiny disk. Most importantly, the crystals are incredibly durable, reportedly as long as 14 billion years, while resisting threats like cosmic radiation.

Arch Mission told TechCrunch that their project has a variety of goals, including protecting human achievements from catastrophes on Earth, and exploring how bulk data transmission might work over the vast distances of space. The group says it wants to put archives “literally around every planet in the solar system that we can get to.”

Arch Mission’s co-founder, Nova Spivack, managed to get a prototype of the group’s archives on the Falcon Heavy after getting Elon Musk’s attention on Twitter. As part of the agreement, though, the group wasn’t able to talk publicly about it before the launch, which is why we’re just hearing about this stellar accomplishment now.